Hawaii, which depends heavily on California visitors, has seen a huge plunge in tourism fueled by sharp fare increases since the bankruptcies two months ago of its two key links to the Bay Area, Aloha and ATA airlines.

Air travel to the islands from California dropped about 25 percent in April, compared with a year earlier, according to data made public this week by Hawaiian tourism officials. It fell nearly 8 percent from all other destinations.

The price of tickets to Hawaii from the Bay Area has shot up about 50 percent, while fares to Hawaii from all U.S. destinations have increased 25 percent, according to Farecast.com. All U.S. air fares generally are up 20 percent from a year ago.

Part of the decline in air travel was due to Aloha halting flights March 31 followed by ATA on April 3. But the main reason Californians aren’t heading to Hawaii isn’t because they can’t get there, a number of travel experts said. It’s mostly because of the soured economy and the increasing cost of travel.

Hawaiian tourism officials say the increase in Hawaii air fares is similar to increases they’ve noticed to other destinations. But that was disputed by Farecast.com. spokeswoman Anne Taylor Hartzell, who said the rising price of Hawaiian fares far outstrips that experienced elsewhere.

In its analysis of round-trip tickets to Hawaii from the Bay Area in the next 14 to 90 days, Farecast.com. found the average price to be nearly $900, compared with $600 last year.

Some of that increase is no doubt due to soaring jet fuel costs, which have prompted many airlines to boost their ticket prices. Moreover, with discount carrier ATA no longer operating, other airlines still flying to Hawaii have less incentive to keep fares down, some experts said.

“With ATA and Aloha being out of business, there just isn’t a whole lot of competition,” said Helen Baldovinos of Let’s Travel in San Jose. She called the price of travel to Hawaii this summer “outrageous, ridiculous, preposterous.”

The California Travel and Tourism Commission doesn’t track air travel out of the state, according to a spokeswoman, and the U.S. Department of Transportation hasn’t yet published national air travel data for April. But the federal agency’s most recent data shows air travel nationally grew by 1.8 percent for the first two months of this year compared with a year ago. So the decline in travel to Hawaii appears to be extraordinary.

ATA and Aloha had averaged about seven trips daily to Hawaii from Oakland International Airport, their Bay Area base of operations. Hawaiian Airlines picked up some of that traffic when it began flying once a day from Oakland to Honolulu on May 1.

“We have been considering a second service to Maui” from Oakland, said Hawaiian Airlines spokesman Keoni Wagner. But he added, “we’re not ready to make any announcements just yet.”

Hawaiian Airlines also flies to Hawaii from Mineta San Jose International Airport.

After ATA and Aloha ceased operations, United Airlines had said it would consider adding flights to Hawaii from San Francisco International Airport. Yet the number of flights from SFO to the islands actually has dropped from 87 in May 2007 to 79 in May this year, said airport spokesman Mike McCarron.

He said those flights now tend to be on bigger planes with more seats, so the number of passengers carried to Hawaii from SFO today “is really comparable” to the number from a year ago. But Hawaiian officials say they’re still facing a big deficit in the number of seats heading to their state, due to the loss of Aloha and ATA.

Some experts said airlines see little economic benefit in adding flights to Hawaii because many vacationers, instead of paying to get there, use their accumulated frequent-flier miles.

Even so, most experts interviewed by the Mercury News said they haven’t heard of people having a hard time obtaining a flight to the islands.

“They have seats available,” said Hawaii’s Tourism Liaison Marsha Wienert, “if people are flexible in regard to their dates of departures.”

Moreover, she noted, a number of hotels are offering promotional deals to lure more visitors. “They range from the third night free, fourth night free, breakfast free, on and on,” Wienert said.

But persuading more people from the Bay Area and elsewhere to visit Hawaii may not be easy. Even before Aloha and ATA stopped operations, concerns about the economy had dampened travel to the islands.

The number of visitors flying there fell 1 percent in 2007 from 2006, according to congressional testimony provided in April by Michael Reynolds, an acting assistant secretary with the U.S. Department of Transportation.

Moreover, he testified, “the figure for visitors from California – who make up 25 percent of Hawaii’s tourist market – fell more than 3 percent in 2007,” which he primarily attributed to the downturn in California’s housing market.

Given the rise in air fares, it may be tough to turn that trend around.

“We’re encouraging our clients to look to other destinations where values remain,” said Marc Casto, president of Santa Clara-based Casto Travel. Besides recommending Southeast Asia and parts of Mexico, he said, “Costa Rica is a great destination for families.”

"I fully support the principles behind Senate Bill 1: to defeat efforts by the president and Congress to undermine vital federal protections that protect clean air, clean water and endangered species," Newsom said in a written statement.